Perforating guns have been adapted for flow into the gun body after being fired as a way to control the local pressure in situations where underbalanced perforating is the goal. The space that held the charges becomes additional volume as a way of local pressure regulation. In some situations discrete flow passages are provided through the gun independently of the location of the shaped charges as in U.S. Pat. No. 5,070,943. In other applications the setting off of the gun opens a non-restricted valve associated with the gun so that production can take place through the gun and subsequent intervention through the gun can take place without reduction in available drift dimension. This design is shown in WO2013/025985 A2.
In some installations the guns are part of a casing string that is properly located and cemented. An inner string with valve assemblies separated by packers is run in and pressure is directed to discrete valves to penetrate the cement and set off discrete guns. The valves are then used in injection service. The valves can be operated through control lines that pass through isolation packers to open or choke for the setting off of the guns or injection. The valves are on an internal string that is run in on a separate trip from the casing that has the guns built into it.
If well flow testing is needed after perforation, the expended gun is typically tripped from the wellbore and a valve assembly is run in the hole and tagged into an existing packer that served to isolate a portion of the wellbore when the gun was suspended below the packer on a running string. The packer, having been set before the gun was fired remains in position as the running string removes the gun and the well test bottom hole assembly is run into the packer for the necessary testing such as drill stem tests.
The present invention saves a trip by delivering the valve or valves that will later be used to flow test or otherwise regulate the well with the gun so that the firing of the gun can be remotely triggered and the regulation of the valve after the gun is fired can also be accomplished by known telemetry techniques or with hydraulic control lines. This allows the completion to progress without a trip in the hole for gun removal and insertion of a BHA to accommodate the valve assembly for subsequent well flow test or shut in procedures. As an alternative a valve that opens on detonation can be used with a tortuous path to control flow. A screen can also be fitted in this alternative design for the flow represented by 24 in the FIG. Using the gun for the flow channel in an axial direction also increases the flow area as compared to use of side mounted guns which add more tortuosity and resistance to flow. These and other aspects of the present invention will be more readily apparent to those skilled in the art from a review of the detailed description of the preferred embodiment and the associated drawing while appreciating that the full scope of the invention is to be found in the appended claims.